Bad tanks, as i myself can cycle between enemies (with quelling strikes) and get agro.
Usually when there is 3 or less enemies and i get agro or close to i switch target and tend to get agro there also. I also tend to wait a bit before attacking since you never know what kind of tanks you get
And i do not always enjoy tanking as blm, lol
Heck i sometimes pull agro from tanks better geared then i...
Like Ageofwar stated sometimes it is probably just best to quickly burn down an enemy